Callidus Design Consulting Engineers

Designers, engineers, consultants and technical specialists covering a wide range of building and process services.

Fume Cupboard largeAir Extract and Exhaust Systems

The ventilation of buildings is of critical importance to maintain appropriate air quality for occupants. Poorly ventilated buildings can result in lower productivity by staff, occupant discomfort and even poor health as a result of excessive internal temperatures or inadequate removal or dilution of pollutants from occupied spaces. In addition to these important factors, ventilation of buildings is often critical to the protection of the building fabric, finished surfaces, furniture and fittings from the effects of moisture or condensation.

Within the UK, minimum ventilation standards for all building types are laid down within the relevant Building Regulations, with further recommendations for specific building applications being provided by the Chartered Institution of Building Services Engineers (CIBSE) and by the HSE via the Local Exhaust Ventilation (LEV) guidance. With the ever increasing pressure on the construction industry to reduce the air permeability/infiltration rates of new buildings in a drive to reduce energy usage, ensuring the provision of appropriate ventilation rates within building spaces has become progressively more important.

With specific reference to foul extract systems, these are normally designated to serve only rooms containing showers or WCs. Given the critical nature of the ventilation provision within these areas to reduce unpleasant atmospheres and damage from moisture & condensation, it is typical to provide a dual fan installation to service these spaces to ensure continuity of extract in the event of a fan failure.

Process extract or exhaust systems are utilised widely within industrial, pharmaceutical and R&D facilities and are usually necessary to remove airborne contaminants which would otherwise be hazardous to health. Such systems may reject contaminants directly to the outside atmosphere if permissible by the local authority, or there may be a requirement to incorporate abatement plant to remove particulate or hazardous gases from the exhaust airstream prior to atmospheric discharge. Such installations would typically include an exhaust scrubber or regenerative thermal oxidiser (RTO). The material selections for such systems is often critical to ensure the longevity of system operation by the avoidance of chemical attack and degradation.

Callidus Design can provide design and specification services for new general, foul and process extract systems, modifications and extensions, condition surveys, refurbishment and troubleshooting.